Hydraulic press and automatic operating system



Nov. 8, 1949 E. M. GREER HYDRAULIC PRESS AND AUTOMATIC OPERATING SYSTEM Filed Feb. 14, 1947 v 4 Sheets-Sheet l EDWARD M' 519651? Nov. 8, 1949 E, M @REER 2,487,126

HYDRAULIC yPRESS AND AUTOMATIC OPERATING SYSTEM Filed Feb'. 14, 1947 e 4 Sheets-Sheet 2 J--I I .i

Nov. 8, 1949 E. M. @REER HYDRAULIC PRESS AND AUTOMATIC OPERATING SYSTEM `4 sheets-sheet 5 Filed Feb. 14, 1947 I i-- Si wv-- ,2x3/1L 1Q n N s@ @s 4 Sheets-Sheet 4 0 f Z m u JJ.. on 4 f|| N f zn%\ n B no WR l 8 3F 0 W, my 4 a Nov. 8, 1949 E. M. @REER HYDRAULIC PRESS AND AUTOMATIC OPERATING SYSTEM Filed Feb. 14, 1947 Patented Nov. 8, 1949 HYDRAULIC PRESS AND AUTOMATIC OPERATING SYSTEM Edward M. Greer, West Hempstead, N. Y., assignor to GreerHydraulics, Inc., Brooklyn, N. Y.

Application Februarylfl, 1947, Serial No. 728,516

7 Claims.

This invention relates to hydraulically operated power presses and their operating system, and more' particularly to the combination of electrical and` hydraulic apparatus to control and automatically cycle the press in operation.

The normal operation of a hydraulic press is old in the art in which hydraulic fluid may be applied to one' side of av piston to produce the power'stroke of the press and to apply the hydraulicL iiuid pressure on the opposite side to returnl the press to an open position. However, in the prior art the'presses that have been utilized toproduce high pressures for a large Work piston have necessarily'been operated by a heavy motor and pump.

It is an object of this invention to utilizea small motor and` high pressure pump with means of storing sufcient fluid for producing the necessary4 Work positioning stroke of a press and utilizing the high pressure developed byy the smaller pump to produce a work stroke on the press.

Another object of this invention is to provide a hydraulic system connected to a power press and a Work positioning cylinder which includesv a pair of sequence valves to' provide means tocontrol the' utilizationy of the hydraulic pressure by the work positioning cylinder and subsequently by the power press and vice versa the opening of the power press and 4sulosequently a return of the Work positioning cylinder to its original position.

Another object of this invention is to provide means tocontrol the flow of `a heating medium to a dieV and, at the same time, control the positioni'ng of said die into a hydraulic press, while storing suiicient hydraulic fluid pressure in an accumulator for positioning the hydraulic press during this cycle `of voperation.

A still further object vof this Vinvention is to provide means to utilize a small velocity high pressure uid pump in combination with an accumulator and chec-k valve to store sufficient hydraulic duid under pressure for the work positioning stroke of a hydraulic cylinder and in addition-to be utilized in 'the hydraulic system so Vthat when the hydraulic cylinder has been positioned in its work positioning stroke by the uid ypressure stored in said accumulator the high pressure i'luid 'flow from said pump will close said 'check valve and vact upon the non-compressible fluid of the piston cylinder producing a static force 'maintaining ya working operation on the hydraulic press.

A still further dbject of this invention yis to utilize a 'time controlled 'switch in combination.

with solenoid operated hydraulic valves in a hydraulic system, said solenoid operatedhydraulic valves controlling the'low of fluid pressure to position a pair of dies in the press and subsequently the Work positioning stroke of said` press, said time switch reversing'said valves ina predetermined time to openA said press and to return said dies to a reloading position.

A further object of this invention isto provide an electrical hydraulic automatic controlling system for the operation of a hydraulic press in which a die is providedv with a heating cycle during its die positioning stroke and during the Work positioning stroke of the power press and means to predetermine a time cycle for cooling the die while the press is closed for its pressing cycle, and means to re-establish the heating cycle while the power press is resuming its initial start-n ing position, and means to reset the wholel circuit for a new cycle of operation.

A still further object of this invention is to ,y provide an electrical control circuit to control the operation of a pair of solenoid operated fluid valves in combination with a die and powerl press, means to control the flow of a heating iiuid through a first valve when the press is operated to heat the die, means to shut 01T the heating iluid ow through the first valve and open a iioW of cooling fluid through the second valve to the die to cool the die, and means to close the second valve and open the rst valveV and rez-establish the heating cycle.

Other objects will be apparent by referring to the detailed description of this device and its operation, as well as the accompanying drawings in which:

Fig. l illustrates a front elevational View of the power press and its die positioning apparatus (illustrated partially in section) Fig. 2 illustrates a side elevational view taken on line 2 2 of Fig. l,

Fig. 3 is a plan view of one half of the die taken on line 3 3 of Fig. l,

Fig. 4 is a plan View of the other half of the die taken on line 4 4 of Fig. l,

Fig. 5 is a schematic illustration of the press in conjunction with the hydraulic and electrical systems utilized in the operation of the press,

Fig. 6 is a cross sectional View taken on line 6 6 of Fig. 1,

Fig. '7 is a .cross sectional vievi7 of a 4double solenoid operated hydraulic valve in which the three positions of the valve are illustrated,

Fig. s is a cross sectional view of a Single solenoid operated hydraulic valve illustrating the two positions of the valve, and

Fig. 9 is a cross sectional view of an unloader valve as utilized in the hydraulic system.

Referring to Fig. 1, there is a power press lll mounted on a work table or casting Il having four supporting columns I2 with a hydraulic cylinder i4 mounted at the top of the columns i2. The hydraulic cylinder I4 is provided with a piston I5 that bears upon the pressure plate I6 of the press, the plate lli oeing slidably mounted on the four columns i2. The work table il` is provided with a track 28v (Fig. 2) in which a die holder 2l is mounted. A work positioning hydraulic cylinder '22 is also affixed to the work table il at one end thereof (Fig. l), the opposite end of the work positioning cylinder having a piston rod 23 extending therefrom which is alxed to the member 2l by means of a yoke 24. The member 2i, in turn, supports the lower portion of a die 25. An upper portion of the die 2B is pivotally axed by pivot '28 to the lower half and in its closed position assumes the position illustrated in Figs. 1 and 2. The die members 25 and 26 are provided with a diffusing coil or channeled aperture 30 to permit the circulation of a heating or cooling medium. The press lil is also provided with a pair of sequence valves 4i? and 4U', the valve 4B being affixed to the member I6, while valve 44 is aflixed to the work table I i. The sequence valves, as illustrated in Fig. 6, are provided with an extended member 35. Valve 4G is so mounted to member I6 that its extension 35,-

in the position illustrated in Fig. l, will bear against the projecting arm 3G which is aixed to the upper portion of the press. Valve 4G is so mounted on table Il that its extension 35, in the position illustrated in Fig. l, will bear against the lower die 25 or its support 2i which moves with the die. illustrated in Fig. 6, are comprised of a housing 3i having a central bore of two different diameters, the small bore 4i and the large bore 42 meeting at a shoulder 43. A valve plunger 44 is mounted through the larger bore 42 so that the valve face 45 will bear against the shoulder 43 and a retaining member 45 is threadably secured in the bore 42 to retain a spring 4l, the spring 4l, in turn, retaining the valve face 45 in its closed position against the shoulder 43. The plunger 44 is also provided with an internal chamber 48 in which a poppet valve 49 is mounted to bear on a shoulder 5u and the valve 49 is retained in this position by a spring 5i. rEhe chamber 48 is provided with an aperture 52 so that it may communicate with the outer bore 42. A bore 54 is provided below the poppet valve 49 and a pair of apertures 55 are provided so that the bore 54 will communicate with a recessed portion 56 of the plunger 44. An inlet port tu is provided in the housing 3l to communicate with the bore 42, while an exhaust port 6I is provided to cornmunicate with the recessed portion 56 of the plunger 44.

It is apparent in operation that fluid pressure entering port Gil cannot pass through this valve in the position illustrated in Fig. 6. It is also apparent that any back pressure backing up through port 6i would lift the check valve 49 and prevent excessive pressure in the system connected to port Si. It is further apparent that a mechanical pressure on the extension 35 will naturally lift the plunger 44 so that its valve face 45 becomes opened and the fluid pressure entering port 60 will be permitted to pass the valve The sequence valves 40 and 4B', as

and out the port 6i. This explains briefly the structure and operation of the sequence valve 4t.

Referring to Fig. 7, we may follow the structure and operation of a double solenoid operated valve lf3. The valve lil in use will be mounted between a pair of solenoids B and C. The valve 10 is comprised of a housing 'H having four ports therein, P, R, C4 and C-2. A plunger 12 is centrally mounted in the housing 'il and is provided with extended metal portions 'i3 and 'M that extend ont through the housing il into the solenoids B and C, and, in operation, control the positioning oi the plunger l2 depending upon which solenoid, in turn, may be energized and when neither solenoid is energized the plunger 12 will assume a balanced or neutral position. The plunger l2 is provided with two enlarged lands l5 and i6. rThe internal portion oi" the housing 'il provides a bore il through which the plunger l2 is slidably tted. There are three positions of the valve 'iii which we will refer to as i, 2 and 3. In position l, with solenoid B energized, the land l5 will prevent the fluid pressure port P, that is connected to the bore T, from communicating with the return port R, which is connected to either end of the bore "il, while the land i6 prevents the pressure port P from communicating with the port C-t, which is also connected to the bore ll. However, this leaves port C-i which is connected to the bore ll, communicating with the port P. Therefore, in this position fluid pressure will pass into the valve and out port C-l, while a return fluid pressure returning through port C-2 will pass into the valve and out port R.

.- It is apparent that when solenoid B is deenergized the valve may be forced by a spring or otherwise to assume the position illustrated at 2, and when the solenoid C is energized the valve will assume the position illustrated at 3. When the value assumes the position 3 the plunger l2 will re-route the flow of fluid through the valve so that pressure entering the port P will pass into the valve and out port C-2, while the return pressure flowing into port Cf-l and into the valve will flow out the port R.

Referring to Fig. 8, which illustrates the single solenoid operated valve 80, this valve is normally in an open position, as illustrated-1in position l, and when the solenoid A is energized it will be in a closed position, as illustrated at 2. Valve is comprised of a housing 8i having a valve plunger B2 mounted centrally therein. The plunger 82 has an extension 83, which extends outside the housing 8| into the solenoid A. The plunger 82 at its opposite end is provided with a valve face 84. The valve face 84 co-acts with a valve seat 85 in its closed position. A pair of chambers 86 and 8'! in the housing 8l are separated by the valve 84 in its closed position. A pressure port P is connected to chamber 36, while a line port L is connected to chamber 81. It is apparent that fluid pressure entering port P will normally iiow through chamber 86 past the valve 84, through chamber 8l and out the line L, but

' when the solenoid A is energized the valve 84 will close and prevent the iiow of uid as described.

Referring to Fig. 9, a pressure control valve is illustrated and is similar to the valve illustrated in the Patent Number 2,264,37 5, issued December 2, 1941, but in the particular use of the valve as illustrated there has been added to this valve a regulating handle which permitsa resetting of the pressure, so that the unloading pressure of this valve may be varied according to the required pressure desired in this system. Any other pres- Heek v el'vje us and ,tde verve I la turn; 4connec t'ed toabn accumulation |4 [4 delineated te e sedree ef eel'd wter aprfe hee catherine msbelne ep fated" vali/'e adz the line Ilz; alsgbeing een; Ar Md selle dydesergibednms d'lejtmg SyStm'S and therontrol relay' R is provided to control d`by a lead |54 to' the main t"R1-l| is also connected to lead [lite slide of the relay coil is* con' g55' t6 elimit switeh e1-' 1' niet' ,ef the' dle`e gaeste" their 14|, by means ef ejleed eeted by d lead 16u te ,ally closed' ewitllj l of eme4 lee erde of swltell'libelng eene; db ye leed 144 eejtlleline ljaz., the relay l; n efcted to the leafdfV |41 on o'nesdeand to ntact onv the other side.V [The`-0'p'V tl ,'lll'sonnected by a lead I 62 to aco' u Q Il; is,"in`tl'l rn, connected tidtlieopeeede ltchiRfel" of the' meinreley of R 'Ithevsolencld operated Valie F is also' con-f n cl by rrn'sni lead |63 to the open Side 0f ljl Qfrelay R, While the opposite side of id Els eeneeetedby e leedl 6 5l terthe swingen b 'elay ,I {v'l'vplheuopposite-sde of switch 1 nhected to the lead |41 which, already described, connects ,to theswitch R'-v2 i-tf1@ mein relay; e tr'l1 witch s-z is c912- d by r''e ns ef le de yIsls andi |461 te the 9p: K,3 The swtchSf-Z member I6 in its downfarspubon an ex'tnsio'n ding ''lltV o; switch Sl-'2.4 `A startey 'e connected to the main relay (y Jl't ndrR- by a lead |45, While the opposlt'; |id of tlle ystart,buttcln I5| is connected @ya lead a te enge vvewitjeh R-r. Lead les Lis y ed'mtg one sfide of tllesto'p button,

the'opi'posite s de ol? the 4stop button is conle eenneetegd by ineens of e leedlss `e ayRhand tollead |55 which is coneStal-t lollttfo'rlV |5 A time switch clfldedwllcn 'lecolnpr'sed of a relay r il@ andaaml! driven by the the .cam l 1| lcoxrltrollingf the positono'f The relay Meel controls the operaitch' |13, ',Ih'e relay 1r\'/['-| v is confeansdo'yfa lead I M to the common lead tedv tev switch Rfof 4relay R. rTlle l A M ed to one side of switch |13 and to ne Side of Aell/Alten V4| 1,2, The relay I on ste 'syicle is', connected by a lead |15 to mll' lea-d |41l vttl'lchv's connected to the 'z ef the m air1 re1ay R. Lead l15 is ted te 'one side olltlleI motor |111, the celte side ofntl'l'e nl c'ltory being. connectedbya l d :1s jeje;[elle` e site slde df elle ewlteh `|13, ele'reids n, B arid arecemlected t@ |12, ende is, -seleneld 'c is connected by a.

e efeetenndlimet ehewn) yley e peur ef leads-' lead |80 to contact |8| and solenoids A and B are connected by means of a lead |49 to a contact |82 of switch |12. The opposite side of solenoids A, B and C are conected by a common lead |41 to the switch R-2 of the main relay R.

In operation, it is necessary to start the hydraulic circuit motor |05 by closing switch |01. This conditions the hydraulic circuit for operation. That is, it produces a fluid pressure with the pump |93 charging through the unloader valve 96 to charge a predetermined pressure in the accumulator H and through the normally open valve 80 to charge the accumulator H4. With this system ready for operation the operator may close the switch That is, when the dies -26 have been properly iilled with the material to be pressed and the dies 25--26 will be positioned on the outermost position of the work table with the hydraulic cylinder 22 having its piston 23 fully extended. Thus the closing of switch |5| will energize solenoids A and B, and relay R, of course, will be energized due to the closing of switch |5| and held energized by the normally closed switch S-|, the potential passing from lead |42 to switch R--2, through lead to switch |5|, through the closed switch, through the lead and |55 back to relay R through the relay and lead |54 to the opposite side of the line. The potential from lead |42 and switch R-2 and lead |46 also passes through switch |5I, through lead |52, through switch S|, through lead |55, through the relay R, through the opposite lead |54 to the main line |41, thus the relay R closes and switch 3 will be closed to form a holding circuit when the button f open so that steam pressure may flow through 4 line |32 to the dies 25 and 26, through their ports t 93 and 92 respectively and out the waste connection. This steam heat medium flows through the dies during the interval of time when the dies are moved into the position illustrated in Fig. 1

and continues while the press cylinder moves downward until it contacts the die 26, at which time the switch S-2 will be tripped by the member i6. The closing of switch S-2 will energize relay K, the potential flowing from lead |42, through switch R-Z of main relay R which is closed, through contact |48 and lead |41 to relay K, through K, through a lead |84, through lead |66, through the closed switch S--2 back through lead |61 to the common lead |63, through the closed switch R| of main relay R, through the lead |54 to the oposite side of the line |4|. Thus, the energizing of relay K will open switch K-I and close switches K-Z and K-3, opening switch K-I thus de-energizes solenoid E closing the steam line. Whereas, closing switch K-2 will energize solenoid F. This may be followed from the main line |42, through switch Rf-2 of main relay R, through line 41 to switch K-2, through the closed switch, through line to solenoid F and back through the common line |63 to the closed switch R--I of main relay R, through lead |54 to the opposite side of the line |4|. When relay K is energized switch K-3 will also be closed. This provides a holding circuit to retain relay K energized until switch S-2 again opens. Thus, with solenoid F energized valve |3| will be opened and a cooling medium, such as water, will flow through line |31 to the dies 25 and 26 to cool them and out the waste line. At the time the main relay R was energized and switch R-l was closed a circuit was also completed from switch R--I through line |63, through line |14, through the relay M-I, through lead |15 to the common lead |41 back through switch R-2 to the opposite side of the source of potential. This closed switch |13 and potential also flowed from line |14, through switch |13, through'lead |16 to the motor |10, through the motor |10 bacl; through lead |15 to the common lead |41 and, as described, back to the opposite side of the source of potential thus causing motor |10 to be operated. The motor |10, in turn, driving cam I1 I Since cam |1| positions the switch |12 it will in its initial position, as illustrated in Fig. 5, close switch i12 against contact |82 and the potential from line |14 will flow through switch |12, through the contact |82, through the line |49 to both solenoids A and B and the opposite sides of solenoids A and B are connected by lead |41 back to the switch R-z and the opposite side of the source of potential thus solenoids A and B are energized and the valve will be closed, as already described,y while the valve 10 will be positioned, as illustrated in position 3 of Fig. '1.

Thus when the main relay R is closed solenoid E is energized and solenoids A and B are energized through the timer |50. In this condition the dies are heated and the hydraulic fluid pressure passing through valve 10 will transfer the dies by means of cylinder '22 to the position illustrated in Figs. 1 and 5. Having arrived at the position illustrated the die 25 will trip valve 40 and the hydraulic fluid pressure will pass out port 6 through the line |22 into port C-Z forcing the press cylinder downward until the member |6 trips the switch 5 2. It should be noted that during the downward movement of the hydraulic cylinder i0, valve 89 is retained in a closed position, therefore, the stored fluid pressure in the accumulator i4 must pass through the check valve M3 to be utilized to supply a sulcient volume of uid to fully position the cylinder through its full stroke until member I6 rests upon the die 26 and it has tripped switch S--2 to its closed position. Since we have already described how relay K is energized by the closing of switch S-2 the control of operation now remains under the action of cam |1|. Thus, as cam |1| rotates it will first break the contact |32 which will deenergize solenoids A and B and as the cam rotates further it will allow switch |12 to close against contact 18|. This completes a circuit to solenoid C energizing the solenoid. The circuit may be followed from one side of the source of potential through lead |14, through the switch |12, contact |21, lead |80, through the solenoid C, through the common lead |41 back to the other side of the source of potential.

It is to be noted that the timer |50 will control 'the time cycle between the timev of closing i the circuit to solenoids A and B, and the deenergization of the solenoids and the energiz'ation of solenoid C, thus a predetermined cycle may be set by the cam |1| and this is governed by the necessary time to position the die, the necessary time to position the press upon the die and the time for the actual pressing operation which completes the iirst half cycle.

" From this point on the return cycle of the press r`and Ydiepositioningk elements are not necessarily timed, but are controlled by a limit switch.

With solenoids A and B de-energized valve 88 will again beopen. whilevalve 1D is released by the -B solenoid, ybut since solenoid C becomes energized it will shift to the position illustrated at position l in Fig. 7. Thus, iiuid pressure entering -valve 'l0 from line H8 passes out of the valve through port C-I and line l2l. Since valve 49 will be in a closed position the uid passes on to the port C -I of the hydraulic cylinder I0. Thus, the main press cylinder will be retracted until the member l, which supports valve 40, reaches a predetermined position when the eX- tension 35 of valve 4E) is tripped opening the valve. At this time the fluid pressure from line 12| will pass through valve 49 out port 6l and through line |24 to port 90 of the cylinder 22. Thus, the hydraulic cylinder 22 will be extended and the dies 25-26 will be moved to the right, Fig. 1, because of their connecting yoke 2 4 until die trips switch S-I. This will break 'the circuit through the main relay R, thus interrupting l the potential supplied through switches Rf-I, R-r-Z and Rf-S to the control apparatus and this will, in turn, (ie-energize solenoid C and the apparatus is prepared for a new cycle of operation.

YIt lis to be noted that the heating cycle will remain on, the heating cycle continuing while the press. closes vupon these dies and the member t6 closes switch S-2 which energizes relay K to ,thus open switch K-I and de-energize solenoid E', thus ending the heating cycle and .at the same time switch K-Z isclosed which controls the energizing of solenoid F starting the cooling cycle. The solenoid F is retained energized until switch S-2 opens (which is the return cyclev of the press)y and when switch S-Z is opened the control switches K-I and K-Z become reversed due to relay K being, de-energized, thus solenoid E is again energized and the heating cycle resumes. This permits retaining the dies in a hot condition so that time is not lost to again heat the dies to asuilicient degree for operation. The cooling cycle has beenso timed and .prearranged with. this .apparatus thata short interval of cooling is sufficient to permit the plastic within the dies to attain a set, so that it maybe removed at the end of the return stroke of the positioning apparatus even though the dies are again heating and preparing themselves for a new charge. K

Having described the apparatus and a complete scquence of operation, according to Fig. 5, it is apparent that the press and its die positioning Yapparatus may be modified without `departing from the spirit of this invention, and it is alsovtrue that the hydraulic `system utilized may be modiiied in any way as long as a .sulicient volume of iiuid at a given pressure is supplied to position the press and .a second high pressure is supplied to be utilized for a pressing operation without departing from the vspirit of this invention, and it is also to be noted that any timing device might be utilized to control electrically, or otherwise, the actual opening and closing of the uid heating valve, the fluid cooling valve and the hydraulic system control valves without departing from the spirit of this invention, and this invention shall be limited only by the appended claims.

What is claimed is:

1. The combination of a press apparatus and a pair of dies, a heating and cooling system for 10 said dies,- and lan automatic operating electrichydraulic system for said press, including a press operable by hydraulic pressure, avdie positioning apparatus operable by hydraulic pressure, a hydraulic pressure source including a pair of solenoid operated Valves and a hydraulic fluid storage accumulator connected to said press, a pair of hydraulic sequence valves, one operable by closing said press and the other operable by positioning a die in said press, apair of solenoid operated valves to control the flow of-a cooling medium anda heating medium tosaid die, an electrical operating system including a timer to control the operation of said rst mentioned pair of valves and the pair of sequence valves as welll as controlling said heatingy and cooling system valves in a sequence of operations, means to open said heating system valve and at the same time operate said positioning apparatus to position said die within said press, means to operate said first sequence valve when said die is positioned in said press to, in turn, position said press for operation with the stored khydraulic fluid, means to close said heating valve and open saidl cooling valve and at the same time hold said press in` operation with a predetermined pressure from said fluid pressure source, means to start said timer operating at the end of said press positioning stroke, means controlled by 'said timer to close said cooling system valve and re-open said heating system valve and at the same time to retract said press to an open position, means to open said second sequence valve when said press reaches its open position and operate said die positioning apparatus to position said die at a re-charging position, and means to recharge said accumulator for another sequence of operation.

2. The combination of a press apparatus and a die, a heating and cooling system for said die and an automatic operating electric-hydraulic system for said press, including a press operable by hydraulic pressure, a die positioning apparatus operable by hydraulicv pressure, a hydraulic pressure source including a pair of solenoid operated valves and a hydraulic iiuid storage accumulator connected to said press, a pair of hydraulic sequence valve, one operable by closing said press and the other operable by positioning a die in said press, a pair of solenoid operated valves to control the iiow of a cooling medium and a heating medium to said die, an electrical operating system including a timer and a pair of limit switches to control the operation of said rst mentioned pair of valves andthe pair of sequence valves as well as controlling said heatF ing and cooling system valves in a sequence of operations, means to open' said heating system valve and at the same time operate said positioning apparatus to position said die within said press, means to operate said iirst sequence valve when said die is positioned in said press to, in turn, position said press for operation with the stored hydraulic fluid, means to close said heating valve and open said cooling valve and at the same time hold said press in operation with a predetermined pressure from said fluid pressure source, means to start said timer operating at the end of said press positioning stroke with said iirst mentioned limit switch, means controlled by said timer to close said cooling system valve and re-open said heating system valve and retract said press to an open position, means to open said second sequence valve when said press reaches its open position and, in turn, operatey said die positio'ning apparatus to position said die at a recharging position and trip said second limit switch and de-energize said solenoid operated valves, and means to recharge said accumulator for another sequence of operation.

3. The combination of a press apparatus and a die, a heating and cooling system for said die and an automatic operating electric-hydraulic system for said press, including a press operable by hydraulic pressure, a die positioning apparatus operable by hydraulic pressure, a hydraulic pressure source including a pair of solenoid operated valves and a hydraulic fluid storage accumulator connected to said press, a pair of hydraulic sequence valves, one operable by closing said press and the other operable by positioning a die in said press, a pair of solenoid operated Valves to control the flow of a cooling medium and a heating medium to said die, an electrical operating system including a timer, a pair of limit switches and a start-stop button with a holding circuit to control the operation of said first mentioned pair of Valves and the pair of sequence Valves as well as controlling said heating and cooling system valves in a sequence of operations, means to open said heating system valve and at the same time operate said position apparatus to position said die within said press, means to operate said first sequence valve when said die is positioned in said press to, in turn, position said press for operation with the stored hydraulic fluid, means to close said heating valve and open said cooling valve and at the same time hold said press in operation with a predetermined pressure from said fluid pressure source, means to start said timer operating at the end of said press positioning stroke with said first mentioned limit switch, means controlled by said timer to close said cooling system valve and re-open said heating system valve and retract said press to an open position, means to open said second sequence valve when said press reaches its open position and operate said die positioning apparatus to position said die at a re-charging position and trip said second limit switch and de-energize said electrical system breaking said holding circuit, and means to re-charge said accumulator for another sequence of operation.

4. A press apparatus according to claim 2 in which the hydraulic fluid storage accumulator is connected to a hydraulic system, which includes a small Velocity fluid flow pump which develops a high fluid pressure, and means to pump hydraulic iiuid pressure from said system through one of said solenoid operated hydraulic valves to store fluid in said accumulator and through the other solenoid operated hydraulic valve to operate said positioning apparatus, and means to utilize the fluid pressure stored in said accumulator to position said press for its pressing operation, and means to subsequently utilize said maximum pressure developed by said pump on said incompressible fluid in said hydraulic press when it reaches its working position.

5. A press apparatus according to claim 4 including a hydraulic system connected to a pair of solenoid operated valves, said hydraulic system including a small Velocity high pressure pump and an unloader Valve to supply a predetermined high pressure flow, said first Valve of said pair of hydraulic Valves being a single solenoid operated Valve and said second valve being a double solenoid operated valve, means to store fluid pressure passing through said first Valve with said accumulator, means to supply fluid pressure from said system through said second valve when a first solenoid is energized to position said die and, in turn, utilize said stored vfluid pressure of said accumulator in positioning said press, and means to de-energize said first solenoid and energize said second solenoid of said second valve to utilize said hydraulic system pressure to return said fiuid press to its open position and to return said positioning apparatus to its re-charging position, and means to re-charge said accumulator through said first valve at the same time.

6. A press apparatus according to claim 4 which includes in said electrical system a pair of relays which, in turn, control the operation of a plurality of switches, said first relay being energized fby said start-stop button and being retained energized by said second mentioned limit switch and, in turn, de-energized when said second mentioned limit switch is opened, and said timer being started when said first mentioned relay is energized, said second mentioned relay being energized with the closing of said first mentioned limit switch and, in turn, de-energized with the opening of said first mentioned limit switch.

7. A press apparatus according to claim 4 including in said electrical operating system a pair of relays which, in turn, control the operation of a plurality of switches, said relays being energized or de-energized by the opening and closing of the said pair of limit switches, said solenoid operated heating valve being energized to an open position when said first mentioned relay is energized, said solenoid operated heating Valve being de-energized .when said second relay is energized and, at the same time, said solenoid operated cooling valve being energized to an open position, and said cooling valve being closed when said second relay is de-energized, while said heating Valve is again energized.

EDWARD M. GREER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,064,162 Hottel Dec. 15, 1936 2,197,528 Makenny et al Apr. 16, 1940 2,371,195 Strauss Mar. 13, 1945 2,373,201 Smith Apr. 10, 1945 2,392,471 ,Fox Jan. 8, 1946 2,398,227 Hubbert Apr. 9, 1946 2,432,215 Stocker Dec. 9, 1947 

